Power Quality; Measurements; Disturbance Recorder; Event Log - ABB REV615 Product Manual

Capacitor Bank Protection and Control
REV615
Product version: 5.0 FP1

7. Measurements

The relay continuously measures the phase currents, the single
or three-phase unbalance currents (with the natural unbalance
current compensated), the symmetrical components of the
phase currents and the residual current.
The standard configuration B includes voltage measurements.
It measures the residual voltage, the phase voltages, the
voltage sequence components and frequency. It also measures
the capacitor bank unbalance voltage if the Uob is connected
and the relay is configured accordingly. This voltage
measurement is called residual voltage measurement, instance
2. The relay offers three-phase power and energy measurement
including power factor.
In addition, the relay calculates the demand value of current
over a user-selectable preset time frames, the thermal overload
of the protected object, and the phase unbalance value based
on the ratio between the negative-sequence and positive-
sequence current.
The measured values can be accessed via the local HMI or
remotely via the communication interface of the relay. The
values can also be accessed locally or remotely using the Web
HMI.
The relay is provided with a load profile recorder. The load
profile feature stores the historical load data captured at a
periodical time interval (demand interval). The records are in
COMTRADE format.

8. Power quality

In the EN standards, power quality is defined through the
characteristics of the supply voltage. Transients, short-duration
and long-duration voltage variations and unbalance and
waveform distortions are the key characteristics describing
power quality. The distortion monitoring functions are used for
monitoring the current total demand distortion and the voltage
total harmonic distortion.
Power quality monitoring is an essential service that utilities can
provide for their industrial and key customers. A monitoring
system can provide information about system disturbances and
their possible causes. It can also detect problem conditions
throughout the system before they cause customer complaints,
equipment malfunctions and even equipment damage or
failure. Power quality problems are not limited to the utility side
of the system. In fact, the majority of power quality problems
are localized within customer facilities. Thus, power quality
monitoring is not only an effective customer service strategy but
also a way to protect a utility's reputation for quality power and
service.
The protection relay has the following power quality monitoring
functions.
12
• Voltage variation
• Voltage unbalance
• Current harmonics
• Voltage harmonics
The voltage unbalance and voltage variation functions are used
for measuring short-duration voltage variations and monitoring
voltage unbalance conditions in power transmission and
distribution networks.
The voltage and current harmonics functions provide a method
for monitoring the power quality by means of the current
waveform distortion and voltage waveform distortion. The
functions provides a short-term three-second average and a
long-term demand for total demand distortion TDD and total
harmonic distortion THD.

9. Disturbance recorder

The relay is provided with a disturbance recorder featuring up to
12 analog and 64 binary signal channels.The analog channels
can be set to record either the waveform or the trend of the
currents and voltages measured.
The analog channels can be set to trigger the recording function
when the measured value falls below or exceeds the set values.
The binary signal channels can be set to start a recording either
on the rising or the falling edge of the binary signal or on both.
By default, the binary channels are set to record external or
internal relay signals, for example, the start or trip signals of the
relay stages, or external blocking or control signals. Binary relay
signals, such as protection start and trip signals, or an external
relay control signal via a binary input, can be set to trigger the
recording. Recorded information is stored in a nonvolatile
memory and can be uploaded for subsequent fault analysis.

10. Event log

To collect sequence-of-events information, the relay has a non-
volatile memory capable of storing 1024 events with the
associated time stamps. The non-volatile memory retains its
data even if the relay temporarily loses its auxiliary supply. The
event log facilitates detailed pre- and post-fault analyses of
feeder faults and disturbances. The considerable capacity to
process and store data and events in the relay facilitates
meeting the growing information demand of future network
configurations.
The sequence-of-events information can be accessed either via
local HMI or remotely via the communication interface of the
relay. The information can also be accessed locally or remotely
using the Web HMI.

11. Recorded data

The relay has the capacity to store the records of the 128 latest
fault events. The records can be used to analyze the power
system events. Each record includes, for example, current,
1MRS757952 D
ABB